A prostate cancer drug that takes a new approach to blocking tumor growth helped more than 40 percent of men with advanced prostate cancer, researchers reported on Tuesday. The drug, made by San Francisco-based Medivation Inc. (MDVN.O), helps stop testosterone from getting into cells and driving the cancer.
Very early phase I/II safety tests in 30 men showed it was safe and might be shrinking tumors, Dr. Chris Tran of Memorial Sloan-Kettering Cancer Center in New York and colleagues reported in the journal Science. Men with advanced prostate cancer are often treated with so-called castration therapy -- drugs that block the production of testosterone, the "male" hormone that drives many prostate tumors. But the cancer cells begin to evade this treatment in many men. The researchers looked for a drug that might work despite this mutation by the cancer cells.
They settled on MDV3100, which worked well in mice. "Of the first 30 patients treated with MDV3100 in a phase I/II clinical trial, 13 of 30 (43 percent) showed sustained declines (by more than 50 percent) in serum levels of prostate specific antigen, a biomarker of prostate cancer," they wrote. Lower levels of PSA suggest that tumors have stopped growing or have shrunk.